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Hypoxic training: Clinical benefits on cardiometabolic risk factors

The main aim of this review was to evaluate the effectiveness of hypoxic training on the modulation of cardiometabolic risk factors.
Literature review.
An electronic search encompassing five databases (PUBMED, EMBASE, MEDLINE, CINAHL, and SPORTDiscus) was conducted. A total of 2138 articles were retrieved. After excluding non-relevant articles, duplications and outcomes not related to cardiometabolic risk factors, 25 articles were chosen for review.
Body weight and body composition were reported to be significantly improved when hypoxic training (≥1700 m) was used in conjunction with exercise regimes, at least three times a week, however extreme altitudes (>5000 m) resulted in a loss of fat-free muscle mass. Fasting blood glucose levels generally improved over time (≥21 days) at moderate levels of altitude (1500 m-3000 m), although reductions in blood glucose tolerance were observed when subjects were exposed to extreme hypoxia (>4000 m). Resting systolic and diastolic blood pressure levels improved as much as 26 mmHg and 13 mmHg respectively, with hypoxic training (1285 m-2650 m) in medicated, stable hypertensive subjects. Effects of hypoxic training when used in combination with exercise training on cholesterol levels were mixed. While there were improvements in total cholesterol (-4.2% to -30%) and low-density lipoprotein (-2.6% to -14.3%) reported as a result of hypoxic training, available evidence does not substantiate hypoxic training for the improvement of high-density lipoprotein and triglycerides.
In conclusion, hypoxic training may be used as an adjunct treatment to modify some cardiometabolic risk factors. Measurement of hypoxic load may be used to individualize and ascertain appropriate levels of hypoxic training.
Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Year: 2014

Authors: Wee J, Climstein M

Source: J Sci Med Sport.

PMID: 24268571

Effect of hypoxic training on inflammatory and metabolic risk factors: a crossover study in healthy subjects.

The purpose of this study was to investigate the influence of hypoxic physical exercise on metabolic syndrome (MS) risk markers and high-sensitivity C-reactive protein (CRP) and to compare its effects on preperitoneal fat, arterial stiffness, and several blood parameters related to MS to those of a control group who trained under normoxic conditions. Fourteen healthy men were examined. Participants performed treadmill exercise 3 days per week for 4 weeks, under either normobaric hypoxic or normobaric normoxic conditions, for 50 min (including a 5-min warm-up and 5-min cool down) after a 30-min rest period. Exercise was performed at a heart rate (HR) corresponding to 60% of the HR at each individual’s maximum oxygen uptake. Training under the different environmental conditions was performed 4 months apart to ensure a sufficient washout period. Waist circumference, preperitoneal fat thickness, brachial-ankle pulse wave velocity, and high-sensitivity CRP after training were significantly lower in the hypoxic group than in the normoxic group. Our results suggest that regular short-term hypoxic training may more effectively reduce arterial stiffness, and thus prevent arteriosclerosis, compared to training performed at a similar exercise intensity under normoxic conditions.

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Year: 2014

Authors: Shi B, Watanabe T, Shin S, Yabumoto T, Takemura M, Matsuoka T

Source: Physiol Rep.

PMID: 24744877

Trends in the use of preconditioning to hypoxia for early prevention of future life diseases

Environmental factors during fetal life program the health outcomes regarding many diseases in future life. This idea has been supported by worldwide epidemiological studies, but the underlying mechanisms are still poorly understood. Three questions should be answered. (i) Does a common underlying cause of ordinary pathological fetal development exist? (ii) If such a cause exists, which mechanism might develop disease in later life? (iii) Is it possible to prevent this underlying cause and therefore the associated obstetric complications to primarily prevent future life diseases? The objective of this review is to attempt to answer these three questions by using PubMed (extending to October 2012) and other sources. Three data-based answers corresponding to these questions were found: (i) hypoxia, (ii) excessive stimulation of neurogenesis, and (iii) preconditioning/adaptation to hypoxia. The method for such preconditioning/adaptation is intermittent hypoxic training (IHT), in which air with low oxygen concentration is breathed through a mask to protect against subsequent strong adverse influences. Data are cited for IHT applications for the prevention/treatment of diseases in different fields, particularly in obstetrics. Data suggested that all common fetal origins of adult diseases are likely predetermined by changes in the fetal brain; therefore, early detection of these changes must be very important. The use of IHT may be a real means to primarily prevent obstetric complications and therefore, prevent future life diseases.

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Year: 2013

Authors: Basovich SN

Source: Biosci Trends

PMID: 23524890